Method for controlling solidification rate of a mold-cast structure

Abstract

A method of controlling a solidification rate of a molten liquid material within a casting chamber to form a solid structure upon controlled cooling thereof. The method includes provision of a stationary mold casting chamber having a plurality of sites with respective surface-temperature or heat flux sensors for determining respective site temperatures or heat withdrawal, and with respective independently operable temperature controllers for regulating each respective site temperature. A data base driven microprocessor receives sensor data and selectively and independently operates each controller in accord with algorithmic commands relative a cooling, and thus solidification, rate for the molten material. The molten material is in the casting chamber, the microprocessor receives and compares sensor data, and regulates in response thereto each respective temperature controller for continuously maintaining a cooling rate equal to chosen extents of solidification over a time period terminating upon solid-structure fabrication.

What is claimed is:  
     
       1. A method of controlling a solidification rate of a molten liquid material within a casting chamber of a mold for forming a solid structure fabricated of said material upon controlled cooling thereof, the method comprising: 
       a) heating the casting chamber to a temperature sufficient to maintain material therein in a molten state;  
       b) monitoring respective temperatures at a plurality of sites within the chamber and comparing each said respective temperature with a plurality of stored temperature measurements relating to respective extents of solidification of molten liquid material at each of said plurality of stored temperature measurements; and  
       c) regulating in response to said monitored respective temperatures temperature control for continuously maintaining a rate of cooling within the casting chamber equal to chosen extents of solidification over a time period terminating upon fabrication of the solid material structure wherein each respective temperature at each respective site is independently regulated.  
     
     
       2. A method of controlling a solidification rate of a molten liquid material as claimed in  claim 1  wherein constant cooling is applied to the chamber. 
     
     
       3. A method of controlling a solidification rate of a molten liquid material within a casting chamber of a mold for forming a solid structure fabricated of said material upon controlled cooling thereof, the method comprising: 
       a) heating the casting chamber to a temperature sufficient to maintain material therein in a molten state;  
       b) monitoring respective heat removal rates at a plurality of sites within the chamber and comparing each said respective heat removal rate with a plurality of stored heat removal rates relating to respective extents of solidification of molten liquid material at each of said plurality of stored heat removal rates; and  
       c) regulating in response to said respective heat removal rates heat removal control for continuously maintaining a rate of cooling within the casting chamber equal to chosen extents of solidification over a time period terminating upon fabrication of the solid material structure, wherein each respective heat removal rate at each respective site is independently regulated.  
     
     
       4. A method of controlling a solidification rate of a molten liquid material as claimed in  claim 3  wherein constant cooling is applied to the chamber. 
     
     
       5. A method of controlling a solidification rate of a molten liquid material within a casting chamber of a mold for forming a solid structure fabricated of said material upon controlled cooling thereof, the method comprising: 
       a) providing a stationary mold comprising a casting chamber with a heat-transferable wall, said wall having a plurality of sites each having in communication therewith a respective surface-temperature sensor for determining a respective temperature at each site and an independently operable respective temperature controller for regulating each said respective temperature at each site;  
       b) providing a microprocessor comprising a plurality of stored temperature measurements each relating to respective extents of solidification of liquid material at each of said plurality of stored temperature measurements, said microprocessor in communication with each respective surface-temperature sensor for receiving each respective temperature at each site and in communication with each respective temperature controller for selective operation thereof;  
       c) heating the casting chamber to a temperature sufficient to maintain liquid material therein in a molten state; and  
       d) activating the microprocessor for receiving each respective temperature at each site, comparing each said respective temperature to said stored temperature measurements, and regulating in response thereto each respective temperature controller for continuously maintaining a rate of cooling within the casting chamber equal to chosen extents of solidification over a time period terminating upon fabrication of the solid structure.  
     
     
       6. A method of controlling a solidification rate as claimed in  claim 5  wherein the respective temperature controllers of the mold comprise respective heaters at each respective site. 
     
     
       7. A method of controlling a solidification rate as claimed in  claim 6  wherein constant cooling is applied to the mold. 
     
     
       8. A method of controlling a solidification rate of a molten liquid material within a casting chamber of a mold to thereby form a solid structure fabricated of said material upon controlled cooling thereof, the method comprising: 
       a) providing a stationary mold comprising a casting chamber with a heat-transferable wall, said wall having a plurality of sites each having in communication therewith a respective heat flux sensor for determining a respective heat removal rate at each site and an independently operable respective temperature controller for regulating each said respective temperature at each site;  
       b) providing a microprocessor comprising a plurality of stored heat removal sates each relating to respective extents of solidification of liquid material at each of said plurality of stored heat removal rates, said microprocessor in communication with each respective heat flux sensor for receiving each respective heat removal rate at each site and in communication with each respective temperature controller for selective operation thereof;  
       c) heating the casting chamber to a temperature sufficient to maintain liquid material therein in a molten state; and  
       d) activating the microprocessor for receiving each respective heat removal rate at each site, comparing each said respective heat removal rate to said stored heat removal rates, and regulating in response thereto each respective temperature controller for continuously maintaining a rate of cooling within the casting chamber equal to chosen extents of solidification over a time period terminating upon fabrication of the solid structure.  
     
     
       9. A method of controlling a solidification rate as claimed in  claim 8  wherein the respective temperature controllers of the mold comprise respective heaters at each respective site. 
     
     
       10. A method of controlling a solidification rate as claimed in  claim 9  wherein constant cooling is applied to the mold.